package com.aisile.utils.common;

import org.apache.commons.codec.binary.Base64;
import org.apache.poi.util.IOUtils;

import javax.crypto.Cipher;
import java.io.ByteArrayOutputStream;
import java.security.*;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;


public class RSAUtils {
    public static final String CHARSET = "UTF-8";
    public static final String RSA_ALGORITHM = "RSA"; // ALGORITHM ['ælgərɪð(ə)m] 算法的意思

    public static Map<String, String> createKeys(int keySize) {
        // 为RSA算法创建一个KeyPairGenerator对象
        KeyPairGenerator kpg;
        try {
            kpg = KeyPairGenerator.getInstance(RSA_ALGORITHM);
        } catch (NoSuchAlgorithmException e) {
            throw new IllegalArgumentException("No such algorithm-->[" + RSA_ALGORITHM + "]");
        }

        // 初始化KeyPairGenerator对象,密钥长度
        kpg.initialize(keySize);
        // 生成密匙对
        KeyPair keyPair = kpg.generateKeyPair();
        // 得到公钥
        Key publicKey = keyPair.getPublic();
        String publicKeyStr = Base64.encodeBase64URLSafeString(publicKey.getEncoded());
        // 得到私钥
        Key privateKey = keyPair.getPrivate();
        String privateKeyStr = Base64.encodeBase64URLSafeString(privateKey.getEncoded());
        // map装载公钥和私钥
        Map<String, String> keyPairMap = new HashMap<String, String>();
        keyPairMap.put("publicKey", publicKeyStr);
        keyPairMap.put("privateKey", privateKeyStr);
        // 返回map
        return keyPairMap;
    }

    /**
     * 得到公钥
     *
     * @param publicKey 密钥字符串（经过base64编码）
     * @throws Exception
     */
    public static RSAPublicKey getPublicKey(String publicKey) throws NoSuchAlgorithmException, InvalidKeySpecException {
        // 通过X509编码的Key指令获得公钥对象
        KeyFactory keyFactory = KeyFactory.getInstance(RSA_ALGORITHM);
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(Base64.decodeBase64(publicKey));
        RSAPublicKey key = (RSAPublicKey) keyFactory.generatePublic(x509KeySpec);
        return key;
    }

    /**
     * 得到私钥
     *
     * @param privateKey 密钥字符串（经过base64编码）
     * @throws Exception
     */
    public static RSAPrivateKey getPrivateKey(String privateKey) throws NoSuchAlgorithmException, InvalidKeySpecException {
        // 通过PKCS#8编码的Key指令获得私钥对象
        KeyFactory keyFactory = KeyFactory.getInstance(RSA_ALGORITHM);
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(Base64.decodeBase64(privateKey));
        RSAPrivateKey key = (RSAPrivateKey) keyFactory.generatePrivate(pkcs8KeySpec);
        return key;
    }

    /**
     * 公钥加密
     *
     * @param data
     * @param publicKey
     * @return
     */
    public static String publicEncrypt(String data, RSAPublicKey publicKey) {
        try {
            Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
            cipher.init(Cipher.ENCRYPT_MODE, publicKey);
            return Base64.encodeBase64URLSafeString(rsaSplitCodec(cipher, Cipher.ENCRYPT_MODE, data.getBytes(CHARSET), publicKey.getModulus().bitLength()));
        } catch (Exception e) {
            throw new RuntimeException("加密字符串[" + data + "]时遇到异常", e);
        }
    }

    /**
     * 私钥解密
     *
     * @param data
     * @param privateKey
     * @return
     */

    public static String privateDecrypt(String data, RSAPrivateKey privateKey) {
        try {
            Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
            cipher.init(Cipher.DECRYPT_MODE, privateKey);
            return new String(rsaSplitCodec(cipher, Cipher.DECRYPT_MODE, Base64.decodeBase64(data), privateKey.getModulus().bitLength()), CHARSET);
        } catch (Exception e) {
            throw new RuntimeException("解密字符串[" + data + "]时遇到异常", e);
        }
    }

    /**
     * 私钥加密
     *
     * @param data
     * @param privateKey
     * @return
     */

    public static String privateEncrypt(String data, RSAPrivateKey privateKey) {
        try {
            Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
            //每个Cipher初始化方法使用一个模式参数opmod，并用此模式初始化Cipher对象。此外还有其他参数，包括密钥key、包含密钥的证书certificate、算法参数params和随机源random。
            cipher.init(Cipher.ENCRYPT_MODE, privateKey);
            return Base64.encodeBase64URLSafeString(rsaSplitCodec(cipher, Cipher.ENCRYPT_MODE, data.getBytes(CHARSET), privateKey.getModulus().bitLength()));
        } catch (Exception e) {
            throw new RuntimeException("加密字符串[" + data + "]时遇到异常", e);
        }
    }

    /**
     * 公钥解密
     *
     * @param data
     * @param publicKey
     * @return
     */

    public static String publicDecrypt(String data, RSAPublicKey publicKey) {
        try {
            Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
            cipher.init(Cipher.DECRYPT_MODE, publicKey);
            return new String(rsaSplitCodec(cipher, Cipher.DECRYPT_MODE, Base64.decodeBase64(data), publicKey.getModulus().bitLength()), CHARSET);
        } catch (Exception e) {
            throw new RuntimeException("解密字符串[" + data + "]时遇到异常", e);
        }
    }

    //rsa切割解码  , ENCRYPT_MODE,加密数据   ,DECRYPT_MODE,解密数据
    private static byte[] rsaSplitCodec(Cipher cipher, int opmode, byte[] datas, int keySize) {
        int maxBlock = 0;  //最大块
        if (opmode == Cipher.DECRYPT_MODE) {
            maxBlock = keySize / 8;
        } else {
            maxBlock = keySize / 8 - 11;
        }
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] buff;
        int i = 0;
        try {
            while (datas.length > offSet) {
                if (datas.length - offSet > maxBlock) {
                    //可以调用以下的doFinal（）方法完成加密或解密数据：
                    buff = cipher.doFinal(datas, offSet, maxBlock);
                } else {
                    buff = cipher.doFinal(datas, offSet, datas.length - offSet);
                }
                out.write(buff, 0, buff.length);
                i++;
                offSet = i * maxBlock;
            }
        } catch (Exception e) {
            throw new RuntimeException("加解密阀值为[" + maxBlock + "]的数据时发生异常", e);
        }
        byte[] resultDatas = out.toByteArray();
        IOUtils.closeQuietly(out);
        return resultDatas;
    }


    // 可逆算法  非对称加密
    public static void main(String[] args) throws Exception {
        Map<String, String> keyMap = RSAUtils.createKeys(1024);
        String publicKey = keyMap.get("publicKey");
        String privateKey = keyMap.get("privateKey");
        // MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQClChNYQs1tq82QEY53ASVE6chNOIY8FYbNI5QsUqhzE01m-xqlx_7tZGSGlO1B00-m6pyAc963HGcBTPYos1yU12a3OkO33ZNYC2YjcwSyZ20GWBmx9SVyT23tmflxpLjvUG6WkO5vkTTJOH4yZDdztVdOjvnxPozkYRI1mYqvnQIDAQAB
        System.out.println("公钥: \n\r" + publicKey);  // 给别的服务器
        System.out.println("私钥： \n\r" + privateKey);  // 自己保存

        //MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCGhfKwFyXVYfbxXPEqnlBo4gGb6JZzHCvYfKVPreGhdxveZmk_sy3UHye6fltIHHZC39GSj77NjiuhTM0RVI-LVrjPopLyXU59nKzdJtC3LIaop9eJAb_oO2EavlvZ54eeuLZDv3amqBj8dXSCyPXBl5nsiOLmHo4P6cZdovd3EwIDAQAB
//MIICdwIBADANBgkqhkiG9w0BAQEFAASCAmEwggJdAgEAAoGBAIaF8rAXJdVh9vFc8SqeUGjiAZvolnMcK9h8pU-t4aF3G95maT-zLdQfJ7p-W0gcdkLf0ZKPvs2OK6FMzRFUj4tWuM-ikvJdTn2crN0m0Lcshqin14kBv-g7YRq-W9nnh564tkO_dqaoGPx1dILI9cGXmeyI4uYejg_pxl2i93cTAgMBAAECgYBPcN7GmoTfJEEefBJ3ZpJ5va3RkmL2i1ZhPAqrqTWrkplElxnkYj3YHKXrfh8N0LEOAPrUIEs_PIwLbz1S1KsHc9MSICzxfU2dumIiO-yKq0aM8Y58ecPWvkDBWCntqa06mzPdT3tkE-kcWcXKbqVjwb3GjuRLnDov5_0flCAIkQJBAM2ia-Mc8DPwSUP5i8Ff7c6EY8TtyMTbnZ0PsP4_-JDYP-Rv-9lyIZueUoFZxxneCY9U6ElsG3Ws_projGGXtVUCQQCneL_vQFbkwOoktdPSzU7ubMo14LOufVZ4pPILtLTFkSqEidpI8Q_1_qaZxh4DrpHfHcouHWKAhJgPembzI3rHAkEAge9GoryPXxJPCT-uumLmPh9Td4UU3qcywaK_oPhFFSk_vhWwmubOK6nv0kIrV8IAYmwxVuuTsli8jJ-yzJvy_QJAM78Rv0FoGAKr1nAAZZBepTkkOgWWP4Im59w_lfJeMPWr54wY0JT704y9uaIHwCd-lyxDPoCB4SgXPCEcEmCSHQJBALzE0AzUXYx9sj8cla3_jbe1mxHMXU6rjsmQYqP9dfCMo2Nt-NWFg9nXvabUUcDzapSE0nu61lFih0q6nBkqoFA
        System.out.println("公钥加密——私钥解密");
        String str = "站在大明门前守卫的禁卫军，事先没有接到\n" + "有关的命令，但看到大批盛装的官员来临，也就\n" + "以为确系举行大典，因而未加询问。进大明门即\n" + "为皇城。文武百官看到端门午门之前气氛平静，\n" + "城楼上下也无朝会的迹象，既无几案，站队点名\n" + "的御史和御前侍卫“大汉将军”也不见踪影，不免\n"
                + "心中揣测，互相询问：所谓午朝是否讹传？";
        String str2 = "熊辉舞" + "|" + "429004199012292675";
        System.out.println("\r明文：\r\n" + str);
        System.out.println("\r明文：\r\n" + str2);
        System.out.println("\r明文大小：\r\n" + str.getBytes().length);
        System.out.println("\r明文大小：\r\n" + str2.getBytes().length);

        String encodedData = RSAUtils.publicEncrypt(str, RSAUtils.getPublicKey("MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCGhfKwFyXVYfbxXPEqnlBo4gGb6JZzHCvYfKVPreGhdxveZmk_sy3UHye6fltIHHZC39GSj77NjiuhTM0RVI-LVrjPopLyXU59nKzdJtC3LIaop9eJAb_oO2EavlvZ54eeuLZDv3amqBj8dXSCyPXBl5nsiOLmHo4P6cZdovd3EwIDAQAB"));  //传入明文和公钥加密,得到密文
        String encodedData2 = RSAUtils.publicEncrypt(str2, RSAUtils.getPublicKey(publicKey));  //传入明文和公钥加密,得到密文
        System.out.println("密文：\r\n" + encodedData);
        System.out.println("密文：\r\n" + encodedData2);

        String decodedData = RSAUtils.privateDecrypt(encodedData, RSAUtils.getPrivateKey("MIICdwIBADANBgkqhkiG9w0BAQEFAASCAmEwggJdAgEAAoGBAIaF8rAXJdVh9vFc8SqeUGjiAZvolnMcK9h8pU-t4aF3G95maT-zLdQfJ7p-W0gcdkLf0ZKPvs2OK6FMzRFUj4tWuM-ikvJdTn2crN0m0Lcshqin14kBv-g7YRq-W9nnh564tkO_dqaoGPx1dILI9cGXmeyI4uYejg_pxl2i93cTAgMBAAECgYBPcN7GmoTfJEEefBJ3ZpJ5va3RkmL2i1ZhPAqrqTWrkplElxnkYj3YHKXrfh8N0LEOAPrUIEs_PIwLbz1S1KsHc9MSICzxfU2dumIiO-yKq0aM8Y58ecPWvkDBWCntqa06mzPdT3tkE-kcWcXKbqVjwb3GjuRLnDov5_0flCAIkQJBAM2ia-Mc8DPwSUP5i8Ff7c6EY8TtyMTbnZ0PsP4_-JDYP-Rv-9lyIZueUoFZxxneCY9U6ElsG3Ws_projGGXtVUCQQCneL_vQFbkwOoktdPSzU7ubMo14LOufVZ4pPILtLTFkSqEidpI8Q_1_qaZxh4DrpHfHcouHWKAhJgPembzI3rHAkEAge9GoryPXxJPCT-uumLmPh9Td4UU3qcywaK_oPhFFSk_vhWwmubOK6nv0kIrV8IAYmwxVuuTsli8jJ-yzJvy_QJAM78Rv0FoGAKr1nAAZZBepTkkOgWWP4Im59w_lfJeMPWr54wY0JT704y9uaIHwCd-lyxDPoCB4SgXPCEcEmCSHQJBALzE0AzUXYx9sj8cla3_jbe1mxHMXU6rjsmQYqP9dfCMo2Nt-NWFg9nXvabUUcDzapSE0nu61lFih0q6nBkqoFA")); //传入密文和私钥,得到明文
        String decodedData2 = RSAUtils.privateDecrypt(encodedData2, RSAUtils.getPrivateKey(privateKey)); //传入密文和私钥,得到明文
        System.out.println("解密后文字: \r\n" + decodedData);
        System.out.println("解密后文字: \r\n" + decodedData2);


    }

}